Just Cool It

Nuclear reactors have been used for decades to generate power. This type of power supply gives nuclear-powered vessels the ability to travel very long distances without refueling. Generation of electricity using nuclear power minimizes air pollution due to the burning of fossil fuels. The heat from radioactive decay processes is used to boil water, creating steam which can then be directed through a turbine to generate electrical power.

Amazing But True

In addition to using water for steam generation, the vast majority of nuclear reactors employ water as a coolant. The specific heat for water is higher than other materials, so this fluid can absorb heat energy from the system. To enhance the cooling ability of the water, it is kept at a high pressure so it does not boil.

Researchers are showing a great deal of interest in liquid sodium cooled nuclear reactors. Although the heat capacity of liquid sodium is less than that of water, the sodium-cooled reactor does not require the coolant to be circulated at high pressure. In addition, the neutrons generated during the fission processes do not lose as much energy when they collide with sodium atoms because the sodium atom is heavier that either an oxygen or hydrogen atom in water. There are drawbacks in that sodium is explosive when it comes in contact with water.

In recent years, work has been done using gas-cooled reactors. Early research employed carbon dioxide, and helium is also currently being studied as a coolant. These reactors have the advantage that the heated gas can be used to create steam or can be fed directly into the turbine system for power generation. Helium is chemically inert, so there is a much lower possibility of damage being done to the reactor system or adverse reactions in case of a leak.